Proposal to standardize provisions for the water depth measurement, reduce the track friction range requirements under the test procedures, clarfy that adhesion performance on wet surfaces (wet adhesion) is required not only for C1 tyres, but also C2 and C3 tyres, update the standards references to ASTM F2493-244, F3611-24, F3676-24, F3675-24 and ISO 4000-1:2024, align the definitions of tread groove and principal grooves with proposals for UN R30 and R54, simplify the wording of the requirements for professional off-road tyres, and correct the transitional provision in paragraph 12.23. to specify approvals “first issued after 31 August 2028”.
26. The expert of IWG WGWT proposed improving the precision of the test method for C1 tyres (ECE/TRANS/WP.29/GRBP/2024/23, GRBP-80-11 and GRBP-80-30). GRBP adopted the proposal, as amended by GRBP-80-11 and requested the secretariat to submit them for consideration and vote at the June 2025 sessions of WP.29 and AC.1 as draft Supplement 3 to the 04 series of amendments to UN Regulation No. 117. Should GRBP adopt another draft amendment to the same series of amendments at its session in February 2025, it would be combined with the above proposal.
| GRBP/2024/23 | |
| GRBP-80-11 | |
| GRBP/2025/13 | |
| GRBP-81-09/Rev.1 |